Universal joint and sealing means for screw pumps



March '1,1967 l QRWDBERG- 3,301,486

UNIVERSL JOINT AND SEALING MEANS FOR SCREW PUMPS Filed July 16, 1965 s Sheets-sheet 1 Ugh March .71, 1967 G. R. LINDBERG 3,397,486

UNIVERSAL JOINT AND SEALING MEANS FOR SCREW PUMPS Filed July 16, 1965 v 3 Sheets-Sheet 5 a g E L: m e5# United States Patent 3,307,486 UNIVERSAL JOINT AND SEALING MEANS FR SCREW PUMPS Gustav Rudolf Lindberg, Valla, Sweden, assigner to Aktiebolaget Flygts Pumpar, Solna, Sweden Filed July 16, 1965, Ser. No. 478,013 Claims priority, application Sweden, Jau. 21, 1965, 817/65 10 Claims. (Cl. 10S-117) This application is a continuation-in-part of application Serial No. 423,909 entitled Universal'loint Iand Sealing Means for Screw Pumps filed on January 7, 1965, now abandoned.

This invention relates to screw pumps of the type incorporating a single rotor acting in conjunction with a xed stator, and more particularly to a new universal joint and sealing device for such pumps.

A known pump of this kind is disclosed in my British Patent No. 972,420, in which pump a rotor having an external single helical thread (i.e., la thread with a single starting point) revolves while simultaneously moving eccentrically in a fixed stator casing having an internal double helical thread (i.e., a thread with two starting points 180 apart), theinternal thread acting in conjuncwith the rotor screw and having a pitch twice that of the rotor thread. The thread of the stator casing is made in some elastic material, e.g., rubber, and between the two pump elements closed voids or pockets are formed, which are moved axially through the pump by continuous moves ment without pulsations. On account of the fact that the rotor executes a compound motion consisting of rotation and a concurrent eccentric movement, the drive needs to be transmitted by universal joints, and to this end a short intermediate shaft provided with universal joints at its 5 ends is usually arranged between the rotor and the driving shaft.

Known pumps of this n-ature are each constructed, almost without exception, with its pressure side on the packing-box side, that is, at the end of the pump where the driving shaft enters the pump body. The reason for this construction is that the conventional packing-box is difficult to seal lagainst the sub-atmospheric pressure which prevails mainly on the suction side, that is, against air penetrating from the outside. Air does not have to leak in in any great amount before the suction capacity of the pump is impaired or lost,`or the inconveniences and risks arise which are yassociated with aeration of the pumping medium. The leakage is Iprimarily due to the packingbox running dry at subpressure and resultant overheating.

However, ,placing the pressure side on the driving side brings considerable inconveniences in its train. The axial force which is exerted on the rotor by the pumping pressure and which may amount to several hundred kilopounds will be directed so that the intermediate shaft and the universal joints are subjected to tension as well as the torque necessary for driving the rotor. The space in the shaft and the rotor is limited and therefore the power transmitting pins in the universal joints cannot always be made as strong as is desirable. As a matter of fact, experience shows that the universal joint coupling in these screw pumps is the weakest point mechanically speaking and in most cases is responsible for pump failure. Another inconvenience is that the packing-box usually has to Ibe dimensioned for high pressures, and such boxes absorb much of the potential driving power.

The present invention has the double object of providing in screw pumps of the type in question, on the one hand, a reliable device at the position where the driving shaft enters the pump Casin-g so that the suction side may be arranged at the driving end and, on the other hand, a universal joint couplingwhich is rendered possible by the ice transposition of the suction and pressure sides, the coupling being subjected to compression instead of tension in such an arrangement. According to the invention this universal joint coupling is formed as two universal joints which are so arranged that the axial force acting on the rotor is completely separated from the forces associated with torque, these two descriptions of forces being borne individually by two distinct elements of each of the universal joints. Y

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIGURE l shows a vertical longitudinal section through a screw pum-p provided with a universal joint and sealing means according to the invention.

FIGURE 2 shows the power transmitting intermediate shaft on a larger scale.

FIGURE 3 shows a section along the line III-III of FIGURE 2.

FIGURE 4 shows, on a larger scale, a portion of FIG- URE l, viz. a central longitudinal section through one rotor end provided with the universal joint.

FIGURE 5 is a similar to FIGURE 4 but shows a modiiication of the universal joint.

FIGURE 6 is a section along the line VI-VI of FIG- URE 5.

FIGURE 7 is a plan View of one of the pin housings (seen from below) which receives the ends of the torque transmitting pin of the modification shown in FIGURE 5, and

FIGURE 8 is a section along the line VIII-VIII of FIGURE 7.

Referring to the drawings, the pump body of the screw pump shown in FIGURE 4l comprises three sections, viz. an inlet section 10, an outlet section 12,.'and, clamped therebetween, a stator sleeve or stator casing 14, the sections being held together by means of tie bolts (not shown) between the inlet and outlet sections 10 and 12, respectively. In the stator sleeve 14 a stator of resilient material (preferably a comparatively hard grade of synthetic rubber) is inserted with an easy slide lit, an external flange 16a formed at one end of thestator being secured in sealing relationship between one end of the stator sleeve 14 and the body section 10. The sleeve is sealed at its opposite end by an O-ring 14a. A passage 18 is formed in the flange 16a between the `end of the stator facing the inlet '10a and the outer peripheral surface of the stator adjacent the flange 16a. This passage l'is for modifying hydraulic grip developed on the outside of the stator and thus provides a kind of automatic hydraulic balancing of the stator, asis further described in our copending application No. 424,0'47, filed January 7, 1965.

The inside or inner peripheral surface of-the stator, which denes the outer boundary of the pumping chamber proper, is formed as a somewhat rounded screw thread having two starting points. A rotor 2t) cooperates therewith, the outside of the rotor being likewise formed `as a screw thread which, however, has onlyone starting point and a pitch only half that of the stator thread. Furthermore, the tip of the rotor thread is more accentuated .and sharper than the tips of the stator thread. Between the rotor and stator, closed pockets or voids are formed which are moved continually axially from the inlet to the outlet during rotation of the rotor while conveying the pumping medium. Concurrently with the rotation of the rotor 20 about its axis, the rotor executes an eccentric movement of amplitude e in the stator 16. For a more detailed description of the cooperation 'between the stator and rotor in a pump of this kind and how the pumping action is brought about, reference is made to the aforementioned British Patent No. .927.420,

As previously stated, the necessary eccentric movement of the rotor in the stator brings 4with it the unavoidable complication that drive from the rotor lfrom a stationary but rotatably mounted input shaft must be by means of some kind of universal joint coupling. In this case, the rot-or 20 is made hollow, the cavity 22 thus formed being closed towards the outlet side 12a of the pump but open towards the inlet side a which is at the same time the drive side, as may be seen from FIGURE 1. The feature of a hollow rotor not only permits the total length of the pump to be smaller but also the rotor to be cooled from the inside by the pumping medium, a facility which is of great importance in many cases. An intermediate shaft 24 is connected between the rotor and an input drive shaft 26, this intermediate shaft being connected at its ends to the rotor 20 at the output end of the rotor and to the driving shaft 26, respectively, by means of universal joints 30, which are formed in accordance with the invention and to which is transmitted the conical swinging movement of the intermediate shaft caused by the eccentric movement of the rotor. These universal joints, which are essential to the invention, will be described in greater detail in the following.

As was pointed out above, the present screw pump is characterized in particular by the feature that its drive side coincides with its suction side and the sealing of the leadin of the driving shaft in the pump body needs to be effective so that air is not sucked along the shaft from the outside into the pump. The shaft lead-in, which is most important to the safe and reliable function of the pump, is shown to the right in FIGURE 1. On the right of the figure is a shaft coupling disc 50 which is rigidly secured by means of a key or spline joint 50a to the outer end of the rather short driving shaft 26 for being drivingly connected to an external prime mover. Inside of the coupling shaft disc 50 there is a double-row angular contact ball bearing 52 and inside of this there is a sleeve or combined guide and ring seal 54 of metal having the same outer diameter, the said two members being received in an end bore 56 in the pump body section 10. The ring 54 (O-ring 54a) engages in sealing relationship a shoulder 56a at the bottom of the bore 56, and the assembly comprising ball bearing 52 and ring 54 is tightened against the shoulder by means of a clamping disc 53 and bolts 58a. In its outerward facing end, the ring 54 is provided with an enlarged recess 5411 which receives a conventional sealing sleeve 60 for shielding the ball bearing 52. In other respects the sleeve or guide and ring seal 54 clears the shaft 26, and between the bottom of the recess 54h and the sleeve 60 there is a space open to the atmosphere `so that liquid, which may possibly leak out when the pump is at rest, can escape.

As shown, the outer race of the ball bearing 52 and the guide ring 54 are rigidly secured in the body; the driving shaft 26 is in turn axially fixed in the inner race lof the ball bearing by said race, a spacer ling 62 and the hub 50b of the coupling flange 50 all being tightened against a shoulder 26a on the driving shaft 26 by means of a central bolt 50c with a washer received in the outer end of the shaft, the Washer abutting upon the hub 50b. Thus the driving shaft 26 is axially fixed but is rotatable in the pump body, and it will be readily appreciated that the shaft with the bearing and clamping structure described can, in conjunction with the application of conventional workshop practice, result in a very accurate alignment and centering in the pump body being attained, particularly in relation to the guide and ring seal 54. This is of great importance to faultless functioning of the rotating sealing mechanism used, as will appear hereinafter.

The problem, which is often diflicult, of providing a seal between a stationary and a rotating part is solved in this case by means of a rotating flat or radial seal where the rotating component, in a manner known per se, is made of carbon.

On the inside of the guide and ring seal 54 is a carbon ring 64 which is slideably disposed on the shaft 26 against which it forms a seal (for instance, by means of an O-ring 64a) and also rotates with the shaft. The inner end of the driving shaft 26 is provided with a head 26b and between this head and the carbon ring 64 a helical compression spring 66 is interposed which urges the carbon ring into engagement with the guide and ring seal 54. The interengaging surfaces of the two rings are face ground and form together an almost perfect rotor seal. However, f-or reliability and trouble-free service of the seal, particularly in the long run, it is important that the carbon ring 64 does n-ot perform any wobbling or tilting movements on the shaft 26 during rotation. Such movements impair the sealing effect between the two rings as well as between the carbon ring and the shaft. The sealing surface between the rings will thus be set exactly at right angles to the axis of rotation. Now the faces of the combined guide and ring seal 54 are ground exactly parallel to one another and at right angles to the axis of the peripheral surface of the ring, which can be done easily, and if the arrangement of ring 54, ball bearing 52 and driving shaft 26 is considered it will be readily appreciated, particularly with respect to the extreme accuracy with which a ball bearing is made, that the plane in which sealing occurs between the rings 54, 64 will lie exactly at right angles to the axis of rotation. The carbon ring 64 will not, therefore, warp but will run in the same plane all the time.

The universal joint 3f) will now be discussed with reference to FIGURES 2-4 as may be seen from FIGURE 2, the intermediate shaft 24 is formed at each end with a ball-shaped head 32 having a semispherical surface 28. Perpendicular to the longitudinal'axis, each head is provided with a through-bore 34 whose center axis passes through the center point -of the spherical surface 28. A pin 36, screw threaded at either end, is arranged in each bore 34. Two nuts, which are provided with tapering ends 38a are tightened on the pin 36. These ends 38a are accommodated in complementary seats 40 arranged, on the one hand, in the closed end of the rotor 20 (see FIGURE 4) and, on the other, in the inner head 26b of the driving shaft (FIGURE 1). The bores 34 could be disposed perpendicular to one another and the arrangement may be clearly seen from FIGURE l.

In accordance with the invention, spherical seats 42 are formed in the bottom of the rotor and in the driving shaft head, which receive the respective intermediate shaft head T52-with its spherical surface 28. The bores 34 provide a certain amount of play around the pin 36 so that the axial force acting on the rotor is sure to be borne by the ball joint surface proper, not by the pins, which if borne y by the latter would be practically a pure shearing force derived from the torque exerted on the rotor. Furthermore, the bores 34 taper somewhat, partly in the planes common to the respective bore and the intermediate shaft 20 (angle a FIGURE 2) and partly in the planes .of the bores perpendicular to theshaft (angle [3, FIGURE 3). The angles a and are of the order 4 and 1.5, respectively. In operation, the intermediate shaft will perform a conical oscillating movement of the total angular displacement 2 arc sin e/ L, which movement causes, on the one hand, `a small turning -movement on the pins 36 and, on the other, a small lateral deviation allowed by the divergence at each end of the respective bores 34. The conicity is introduced in order that the torque be transmitted by line contact between the pins 36 and the walls of the bore 34, as indicated in FIGURE 3.

In this way the forces developed during operation of the pump and necessary for driving the rotor are transmitted by very rigid and strong universal joints wherein axial forces and forces of torque (shearing forces) are completely separated and transmitted individually by the respective elements. As pointed out above, the universal joint arrangement according to the invention has been rendered possible by the provision of a safe vacuum lsjeal at the lead-in of the driving shaft into the pump ody.

In the universal joint shown in FIGURE 4, oscillating movement of the intermediate shaft 24, which will cause the torque transmitting pin 36 to slip or slide a little in its bore 34, causing the pin to wear, is unavoida'ble. In FIGURES 5-8 a modification of the universal joint is shown whereby wear on the pin is considerably reduced. In this modification the pin is free so it is permitted to convert, to an extent quite satisfactory from a practical point of view, its sliding and rubbing movement into a rolling movement, whereby the wear on the pin is reduced into a minimum.

In FIGURE 5 the intermediate shaft of the pump is designated by 72 and the pump rotor driven by said shaft is designated by 70. The rot-or 70 and the shaft 72 are interconnected =by means of the modified universal joint according to the invention. The opposite end (not shown) of the intermediate shaft 72 is connected t-o the driving shaft of the pump by means of a second modied universal joint, this of course being identical with that of FIGURE 5.

In the modified universal joint shown in FIGURES 5 to 8, the torque is transmitted to the rotor by a cross pin 74 passing through the bore 34 in the ball-shaped head 32 and engaging by its ends in a pair of pin housings 76 secured to the rotor, said housings being further described below. As in the previous embodiment of the joint, the axial forces and the torque are maintained completely separated and by arranging for there to be suitable play on the -pin S4 it is ensured that the pin is not exposed to any stresses caused iby axial forces.

`On the outside of the rotor 70 two longitudinal, diametrically opposed, rather shallow grooves 78 are milled in the rotor end, each such groove receiving its pin housing 76 snugly. The pin housings are secured in their posit-ons by means of their respective screws 8) which engage -a diametrical screw threaded bore 82, for both screws, in the rotor end beyond the spherical seat 4.2. The screws have preferably cylindrical heads with hexagonal recesses, said head-s being countersunk in the pin housings 76.

The pin housings, see FIGURES 7 and 8, have the form of a parallelepiped and comprise suitable elements of stainless temperable steel which are precision cast to finished size. They are each provided with a stepped through-bore 84 for the screw 80 and are further formed with a rectangular chamber 86, which opens inwardly to receive the end of the pin 74.

As shown, the pin 74 has a simple straight cylindrical form with square ends and is retained in its place by the bottom of each chamber 86. As in the previous construction, the through-bore 34 in the ball-shaped end 32 of the intermediate shaft 72 is formed somewhat double-conical so that its walls diverge outwardly from the center. Here, as hereinbefore described, the conicity is a in the plane common to the bore and the intermediate shaft (FIGURE 5), whereasthe conicity is in the plane of the bore perpendicular to the shaft (FIG- URE 6). The angle a is greater than ,8, and the wall of the bore may be provided at 34a (see FIGURE 6) with small flat, or almost flat, wedge-formed surfaces.

A comprision between vFIGURES 5 and 6 will Ishow how the driving torque is transmitted and how the pinv 74 operates. It is assumed that the rotation takes place clock-wise, as viewed in FIGURE 6, the ball end 32 of the intermediate shaft then driving the pin 74, the pin in turn rotating the rotor by engagement with the pin housings 76. From FIGURE 6 it may be further seen how the pin makes contact with the pin hou-sings and the intermediate shaft, respectively. Here the conicity is so adjusted in relationship to the diameter of the bore that line contact arises between the -pin and the walls of the bore 34 and, in addition, the play between the pin and the side walls of the pin housings 76 is moderate, so practically speaking, line contact occurs here also.

When the screw rotor is rotating with concurrent eccentric movement in the stator body the intermediate shaft 72 will execute conical oscillating movement, which means that the shaft and its ball end 32 will oscillate, on the one hand, about the longitudinal axis of the pin 74 and, on the other, about an axis through the center C of the spherical surface and thus of the ball end, said axis being perpendicular to said longitudinal axis and the longitudinal axis of the intermediate shaft. The lastmentioned oscillating axis (through C) is thus perpendicular to the plane of FIGURE 1. A simple consideration of the movements being executed shows that the pin 74 will roll to and fro in the bore 34 and the chamber 86 while yoscillating about the center C, the chambers accommodating the movement of the pin end in the longitudinal direction of the rotor, see FIGURE 5. In order to roll completely without sliding, the pin should of course be provided with a certain conicity, but as the movements are extremely small, this has no practical significance, but the -pin 74, thus free or floating, will transmit the torque while rolling, and the wear due to sliding movement is practically eliminated.

From the above it. will ybe seen that from a theoretical standpoint the conicity (see FIGURE 6) may equal zero or almost zero. However, in such a case the tolerances of the coacting parts 70, 72, 74, 76 will become unnecessarily narrow. Nevertheless, the construction as a whole has the advantage that play is allowable and desirable.

The universal joint as a -whole is preferably shielded or sealed by means of an O-ring seal 88 which surrounds the ball end 32 immediately inside of the pin 74, as shown in FIGURE 5. Dirt and foreign matter are thereby prevented from entering between the bearing surfaces.

Thus a simple universal joint is provided which is very wear resistant owing to transmission of the torque by the pin with rolling which is made possible by the free or floating mounting of the pin. Here it should be noted that the invention is of course not limited to the embodiments of the universal joint shown in the drawings and here'described, further modification of the joint ybeing possible and within the scope of the invention. As to the structure shown in FIGURES 5 to 8, particularly in small pumps, the housings 74 could, for instance, be made in one piece in the form of a caliper-like device which is pushed onto the rotor from the end, the chamber' 86 then being openv at one side for entry of the pins 74.

The embodiments of the invention in which an exelusive property or privilege is claimed are defined as follows:

1. In a screw pump driven for operation by a rotational input to a drive shaft, the combination comprising:

a body having an inlet port and an outlet port;

sealing means provided around said drive shaft adjacent said inlet port;

a stator having an internal helical thread fixed within said body between said inlet port and said outlet port;

a rotor having an external helical thread, said rotor Ibeing mounted for rotation and concurrent eccentric movement within the stator in cooperation with said stator thread;

. an intermediate shaft connected at opposite ends to said drive shaft and said rotor;

at least one of said connections comprising universal joint means consisting of a lball-and-socket joint and a cross pin extending diametrically through said ball and socket and secured to said rotor;

whereby a high pressure output in said outlet port causes said rotor and said intermediate driven shaft to be urged axially toward said inlet port wherein said balland-socket joint will receive exclusively said axially directed forces and said cross pin will transmit torques acting on said rotor from said rotational input to said drive shaft.

2. The device defined in claim 1, wherein said intermediate shaft is formed with spherical ends having transverse bores therethrough, said bores receiving pins, the axis of said bores intersecting the axis of said intermediate shaft and the central point of the spherical surface of the ends of shaft, said pin associated with one of said universal joints being secured rigidly to said rotor, said rotor being provided at the point of securement with a spherical- 1y concave seat having its central point on the axis of said pin so that said seat and the corresponding end of said intermediate shaft together form said ball and socket joints, whereas said pin associated with the other universal joint is correspondingly secured to the inner end of said drive shaft and comprises a spherically concave seat on said inner end of said drive shaft, said seat forming with the adjacent spherical end of said intermediate shaft a second ball and socket joint.

3. The device delined in claim 2, wherein said transverse lbores in said ends of said intermediate shaft have clearance around their respective pins, said clearance being suiiicient to ensure that the axial force acting on said intermediate shaft is received by said ball and socket joints exclusiveiy and the walls of said bores conically diverging from a minimum diameter at the midpoint of the length of said bore adjacent t-he center point of the spherical seating surfaces of said ends of said intermediate shaft, so that the conicity in a first plane common to the respective bore and said axis of said intermediate shaft accommodates the oscillating movements of said intermediate shaft, and the conicity in a second plane, perpendicular to said first plane, throu-gh the axis of said bore, permits said pin to transmit the torque of said rotor in line contact with said walls of said bore.

4. The device defined in claim 2, yw-herein said pinreceiving bores in said ends of said intermediate shaft are perpendicular to one another.

5. The device defined in claim 1, wherein said rotor is hollow, the end whereof which faces the outlet of the pump is closed and is provided with a concave seat.

6. The device defined in claim 2, wherein said pins are secured to said rotor and said inner end of said drive shaft by means of nuts in threaded engagement with the ends of said pins, said nuts provided with tapering end portions which engage correspondingly formed tapering seats in said rotor and said inner end of said drive shaft.

7, The device defined in claim l, wherein said torquetransmitting and torque-receiving cross pins comprise straight cylindrical studs each passing with clearance through its respective bore in said ends of said intermediate shaft and said studs having their ends accommodated in diametrically opposed housings provided on the outside of said rotor and secured thereto, said pins being arranged free and iioating in said bores of said intermediate shaft and in said housings, whereby said intermediate shaft oscillating movement caused by the eccentric movement of said rotor causes the pins to undergo a rolling movement while transmitting the torque.

8. The device defined in claim '7, wherein said housings comprise metal blocks each snugly accommodated in a longitudinal groove in the end of said rotor and said drive shaft, the edges of said grooves ypreventing said housings from sliding in said direction of the transmitted force.

9. The device defined in claim l, wherein said sealing means comprises a surface-ground carbon ring arranged on said drive shaft and sealingly engaged therewith and rotating in unison with said shaft, said ground end surface of said carbon ring being held by a sprin-g in engagement wit-h a surface ground end of a ring seal which is insertable together with a ball or roller bearing into a bore extending from the outside of the pump lbody, said ring seal being tightened by suitable means against a shoulder at the bottom of said bore, the ends of said ring seal which face said carbon ring and said ball, bearing being parallel so that said drive shaft' is permitted to rotate with its axis exactly at right langles to the sealing plane between said ring seal and said carbon ring.

19. The device defined in claim 9, wherein the end of said seal ring is provided with a recess adapted to Vreceive a sealing sleeve which surrounds said drive shaft for protecting said ball bearing lying outside thereof, a space being provided in said ring 'between the bottom of said recess and said sealing sleeve, said space communicating with the surrounding atmosphere so that any pumping Imedium leaking out can freely escape.

References Cited by the Examiner UNITED STATES PATENTS 2,212,417 8/1940 George 103-117 2,527,673 10/1950 Byram 103-117 2,765,114 10/1956 Chang 103-117 DONLEY J. STOCKING, Primary Examiner.

MARK NEWMAN, Examiner.

R. M. VARGO, W. J. GOODLIN, Assistant Examiners. 

1. IN A SCREW PUMP DRIVEN FOR OPERATION BY A ROTATIONAL INPUT TO A DRIVE SHAFT, THE COMBINATION COMPRISING: A BODY HAVING AN INLET PORT AND AN OUTLET PORT; SEALING MEANS PROVIDED AROUND SAID DRIVE SHAFT ADJACENT SAID INLET PORT; A STATOR HAVING AN INTERNAL HELICAL THREAD FIXED WITHIN SAID BODY BETWEEN SAID INLET PORT AND SAID OUTLET PORT; A ROTOR HAVING AN EXTERNAL HELICAL THREAD, SAID ROTOR BEING MOUNTED FOR ROTATION AND CONCURRENT ECCENTRIC MOVEMENT WITHIN THE STATOR IN COOPERATION WITH SAID STATOR THREAD; AN INTERMEDIATE SHAFT CONNECTED AT OPPOSITE ENDS TO SAID DRIVE SHAFT AND SAID ROTOR; AT LEAST ONE OF SAID CONNECTIONS COMPRISING UNIVERSAL JOINT MEANS CONSISTING OF A BALL-AND-SOCKET JOINT AND A CROSS PIN EXTENDING DIAMETRICALLY THROUGH SAID BALL AND SOCKET AND SECURED TO SAID ROTOR; WHEREBY A HIGH PRESSURE OUTPUT IN SAID OUTLET PORT CAUSES SAID ROTOR AND SAID INTERMEDIATE DRIVEN SHAFT TO BE URGED AXIALLY TOWARD SAID INLET PORT WHEREIN SAID BALLAND-SOCKET JOINT WILL RECEIVE EXCLUSIVELY SAID AXIALLY DIRECTED FORCES AND SAID CROSS PIN WILL TRANSMIT TORQUES ACTING ON SAID ROTOR FROM SAID ROTATIONAL INPUT TO SAID DRIVE SHAFT. 